package javaIO;

import java.io.File;
import java.io.FilenameFilter;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.regex.Pattern;

public final class Directory {
    public static File[] local(File dir, final String regex) {
        return dir.listFiles(new FilenameFilter() {
            private Pattern pattern = Pattern.compile(regex);

            @Override
            public boolean accept(File dir, String name) {
                return pattern.matcher(new File(name).getName()).matches();
            }
        });
    }

    public static File[] local(String path, final String regex) {
        return local(new File(path), regex);
    }


    public static class TreeInfo implements Iterable<File> {

        public List<File> files = new ArrayList<File>();
        public List<File> dirs = new ArrayList<File>();

        @Override
        public Iterator<File> iterator() {
            return files.iterator();
        }

        void addAll(TreeInfo treeInfo){
            files.addAll(treeInfo.files);
            dirs.addAll(treeInfo.dirs);
        }

        public String toString(){
            return "dirs: "+PPrint.pformat(dirs) +
                    "\n\nfiles" + PPrint.pformat(files);
        }
    }

    public static TreeInfo walk(String start,String regex){
        return recurseDirs(new File(start),regex);
    }

    public static TreeInfo walk(File start,String regex){
        return recurseDirs(start,regex);
    }

    public static TreeInfo walk(File start){
        return recurseDirs(start,".*");
    }

    public static TreeInfo walk(String start){
        return recurseDirs(new File(start),".*");
    }

    static TreeInfo recurseDirs(File startDir,String regex){
        TreeInfo result = new TreeInfo();
        for (File item:startDir.listFiles()){
            if (item.isDirectory()){
                result.dirs.add(item);
                result.addAll(recurseDirs(item,regex));
            }
            else{
                if (item.getName().matches(regex)){
                    result.files.add(item);
                }
            }
        }
        return result;
    }

    public static void main(String[] args){
        if (args.length == 0){
            System.out.println(walk("."));
        }
        else{
            System.out.println(args[0]);
        }
    }
}
